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post #5 of (permalink) Old 01-27-2014, 10:30 AM Thread Starter
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Join Date: Jul 2007
Posts: 3
Re: Question for PSIG

Originally Posted by PSIG View Post
There is not much negative to say about them. Compared to the GM TBI, they fit standard 2-barrel manifolds, use common and inexpensive Bosch-style injectors, and have carb-style warm-up and idle air control. The GM TBI has larger throttle bores in some versions, and... well, that's about the only advantage, if it's even necessary. The funny thing is that the larger bores are great, except you can't flow more fuel for HP without very expensive injectors. Catch 22. Both have integrated throttle position sensors and fuel pressure regulators as well, so they are virtually self-contained EFI systems. Add an air and a coolant temp sensor, 40 psi fuel supply and a cheap ECM. Done.

The GM TBI is usually mentioned, because years ago it was the easiest ECM to hack. That is obviously irrelevant these days, and so that makes the CFI the more attractive option for carb conversions on mild to moderate street engines.

Yes, I've helped several guys with upgrading or carb-to-CFI conversions. Most folks prefer the HO units (Mustangs and Lincoln Marks) not only for their larger venturis, but their idle air control scheme. Reality is you can easily open the bores on V6 and lo-po 5.0 versions to HO specs, and remove the 'choke' if you like, but it works fine. So, if you have one of the smaller versions, you can port the venturis and swap the injectors for bigger ones. No need to hunt or pay high for an HO unit.

I've done stock and near-stock Fords and a Dodge with CFI. I've also modded a set of three for a 2x3 tri-power-style setup, though I did not do the final installation and tuning on that one. I've also had my hand in a bunch of custom TBI setups, and drive one of them regularly. That one was done with one of the first MS1s many years and approaching 100,000 miles ago, and still runs like a champ. It has saved it's cost several times over just in increased MPG, and the gravy is the added power.

So, I hope that answers some of your questions. Now I'll assume some questions and answer -
  • Yes, you can piggyback a MegaSquirt onto your existing setup, having it control the injectors and let the stock EEC control the rest. Super easy.
  • Yes, I would strongly recommend adding a wide band O2 like the Innovate LC-1 to the setup for easiest and most effective tuning.
  • Yes, you will see a bump in both performance and mileage on an '85 302 LTD (my daughter had one).
  • No, you do not want to take someone's tune and try it. Start from scratch. Seriously - it's easier and better in the long run.
  • An MS1 or MS2 is fine. Anything more advanced is a waste, as you dont have SEFI or an electronic transmission. A v3.0 board is preferred over the v2.2 as it has built-in control for any kind of injectors, including the low-ohm injectors in CFI/TBI.
  • Find some of my MS posts about tuning throttle body setups. There are a couple tricks that make it easier and more effective.
  • Software? The free MegaTune and a copy of Mega Log Viewer works well -or- a paid copy of Tuner Studio MS ($60).
  • Build your kit straight out of the manual (about 2 hours if you take your time), and set the ignition option for Ford TFI. Or, order it assembled for that.
  • If you're handy with wiring, make your own harness. It won't be complicated. If you're not into that, get the pre-made harness from DIYAutotune.
  • Ask questions. Skim (don't think too hard) the MegaManual. Ignore info that is not about your specific setup. Skim the manual again. The second time stuff will start to make sense. Ask questions.
  • When you install the MS hands-on, it will rapidly all start making sense. Don't wait until you think you understand it all. Just do it. After you get it going, you'll wonder why you didn't do it sooner.

Hey David,

Thanks for all the great info! I can remember way back when that MegaScott used CFI and MegaSquirt on his 68 Cougar and that he had an issue with the choke and fast idle not working. How did you address that problem?

Thanks, boway
boway is offline  
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